I just installed calibre v3.37 and now every plugin I use which manipulates CSS is inaccessible.

I tried to revert to my older run-from-source calibre, which I last updated about a week ago. Unfortunately this doesn't work either. This is the error message I got when I tried to start up my run-from-source version

Code:

calibre, version 3.36.0
ERROR: Startup error: There was an error during calibre startup. Parts of calibre may not function. Click Show details to learn more.
Traceback (most recent call last):
File "D:\JS_git_devel\cal\src\calibre\gui2\main.py", line 289, in initialize_db_stage2
File "D:\JS_git_devel\cal\src\calibre\gui2\main.py", line 228, in start_gui
File "D:\JS_git_devel\cal\src\calibre\gui2\ui.py", line 157, in __init__
File "D:\JS_git_devel\cal\src\calibre\gui2\ui.py", line 171, in init_iaction
File "D:\JS_git_devel\cal\src\calibre\customize\__init__.py", line 612, in load_actual_plugin
File "importlib\__init__.py", line 37, in import_module
File "D:\JS_git_devel\cal\src\calibre\gui2\actions\catalog.py", line 13, in <module>
File "D:\JS_git_devel\cal\src\calibre\gui2\tools.py", line 16, in <module>
File "D:\JS_git_devel\cal\src\calibre\gui2\convert\single.py", line 18, in <module>
File "D:\JS_git_devel\cal\src\calibre\gui2\convert\look_and_feel.py", line 13, in <module>
File "D:\JS_git_devel\cal\src\calibre\gui2\convert\look_and_feel_ui.py", line 290, in <module>
File "D:\JS_git_devel\cal\src\calibre\gui2\css_transform_rules.py", line 13, in <module>
File "D:\JS_git_devel\cal\src\calibre\ebooks\css_transform_rules.py", line 11, in <module>
ImportError: No module named cssutils.css

There have been multiple bugs opened against cssutils for years some even with attached patches that have not been merged. The original owners lost interest a while back, there was a new maintainer and he also lost interest a couple of years ago.

It's open source, anyone who wants to can use it. Like all the various other bits of calibre infrastructure I maintain, such as html5-parser, rapydscript, mechanize, python2, unrardll, dukpy, etc. etc.